JP2019132235A - On-vehicle internal combustion engine - Google Patents

Abstract

To provide an internal combustion engine which inhibits a situation that oil accumulating on a cylinder head does not flow into an oil chamber smoothly and can inhibit reduction of an amount of the oil stored in an oil pan.SOLUTION: A first oil chamber 50 is formed by closing a first recessed part 41 provided on a cylinder block 11 with a cylinder head 12. The cylinder head 12 is provided with multiple communication passages 55 to 57 which open on the upper surface 121 and are connected with the first oil chamber 50. The cylinder block 11 is provided with an oil passage 70 which allows communication between the first oil chamber 50 and an interior of an oil pan. A first opening position 55a, in which the first communication passage 55 opens, on the upper surface 121 is located blow second opening positions 56a, 57a, in which the second communication passages 56, 57 open, on the upper surface 121. A first extension wall 58 is provided between the first opening position 55a and the second opening positions 56a, 57a on the upper surface 121.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an on-vehicle internal combustion engine configured to return oil from above a cylinder head to an oil pan through a cylinder head and a cylinder block.

  In the internal combustion engine described in Patent Document 1, an oil chamber is formed by closing a recess provided in a cylinder block with a cylinder head. The oil on the cylinder head flows into the oil chamber via a communication path provided in the cylinder head. The oil accumulated in the oil chamber returns to the oil pan through an oil passage provided in the cylinder block.

  The oil chamber is disposed on the opposite side of the cylinder across a water jacket formed inside the cylinder block. And since the oil which circulates through an internal combustion engine is cooled with the cooling water which distribute | circulates a water jacket, the oil chamber is formed so that the volume of an oil chamber may become large, and it may extend in a cylinder arrangement direction. The cylinder arrangement direction is a direction in which a plurality of cylinders are arranged in the cylinder block.

JP 2014-114711 A

  By the way, if the amount of oil flowing into the cylinder head increases due to an increase in engine speed or engine load factor, the amount of oil flowing into the oil chamber through the communication path increases, and the pressure in the oil chamber increases. Becomes higher. Further, when the engine speed and the engine load factor increase, the pressure in the crankcase and the oil pan of the internal combustion engine may increase. When the pressure in the crankcase or the oil pan rises in this way, blow-by gas in the crankcase flows backward through the oil passage and flows into the oil chamber. As a result, not only oil but also gas such as blow-by gas accumulates in the oil chamber. And if the pressure in an oil chamber becomes high, the pressure of the gas residence area | region which is an area | region where gas will remain in an oil chamber will also become high. When such a gas retention region is formed in the vicinity of the connection portion of the oil chamber with the communication passage, the gas in the gas retention region prevents oil from flowing into the oil chamber from the cylinder head via the communication passage. As a result, the amount of oil that returns to the oil pan through the oil chamber decreases, and the amount of oil stored in the oil pan decreases.

  Therefore, there is room for improvement in that the oil on the cylinder head is less likely to flow into the oil chamber via the communication path.

  In an in-vehicle internal combustion engine for solving the above problems, an oil chamber is formed by closing a recess provided in a cylinder block with a cylinder head. The cylinder head is provided with a plurality of communication passages that are open on the upper surface of the cylinder head and connected to the oil chamber, and are arranged in the cylinder arrangement direction, which is a direction in which a plurality of cylinders are arranged in the cylinder block. A passage is arranged. The cylinder block is provided with an oil passage for returning the oil staying in the oil chamber into the oil pan. The first opening position, which is the position where the first communication path of each communication path opens on the upper surface of the cylinder head, is the second communication path of the communication paths on the upper surface of the cylinder head. It is located below the second opening position. An extending wall extending in the direction intersecting the cylinder arrangement direction is provided between the first opening position and the second opening position on the upper surface of the cylinder head.

  According to the above configuration, the upper surface of the cylinder head is configured such that the first opening position is located below the second opening position. Further, an extending wall is disposed on the upper surface of the cylinder head between the first opening position and the second opening position. Therefore, the oil that has flowed onto the cylinder head is more easily guided to the first opening position than the second opening position, and easily flows into the first communication path. That is, the oil on the cylinder head is difficult to be guided to the second opening position and hardly flows into the second communication path. Therefore, since the gas staying in the oil chamber can be discharged out of the oil chamber via the second communication path, the amount of gas that stays in the oil chamber can be reduced. As a result, when the oil on the cylinder head flows into the oil chamber via the first communication passage, the gas staying in the oil chamber prevents the oil from flowing into the oil chamber via the first communication passage. It becomes difficult.

  Therefore, according to the said structure, it becomes possible to suppress that the oil on a cylinder head becomes difficult to flow into an oil chamber, and to suppress the reduction | decrease in the amount of oil storage in an oil pan.

  In addition, it is preferable to arrange | position the connection part with the oil passage in an oil chamber near the connection part with the 2nd communication path in an oil chamber rather than the connection part with the 1st communication path in an oil chamber. According to this configuration, the gas flowing into the oil chamber from the oil pan side through the oil passage is connected to the second communication passage in the oil chamber rather than in the vicinity of the connection portion with the first communication passage in the oil chamber. It tends to stay in the vicinity of the part. Therefore, the gas staying in the oil chamber can be easily discharged out of the oil chamber through the second communication path, and the oil staying in the oil chamber can be used to oil from the cylinder head through the first communication path to the oil chamber. It is possible to increase the effect of suppressing the distribution of

  The cylinder block may be provided with a partition wall that divides the oil chamber into a first oil partition chamber and a second oil partition chamber adjacent to the first oil partition chamber in the cylinder arrangement direction. The first oil dividing chamber is connected to the first communication passage, while the second communication passage and the oil passage are not connected. While one communication path is not connected, the second communication path and the oil path may not be connected. In this case, the partition wall is preferably provided with a through hole that allows the first oil dividing chamber and the second oil dividing chamber to communicate with each other.

  According to the above configuration, the gas that has flowed back through the oil passage flows into the second oil dividing chamber. Since the partition wall is arranged between the second oil dividing chamber and the first oil dividing chamber, it is possible to suppress the gas staying in the second oil dividing chamber from flowing into the first oil chamber. . For this reason, it is difficult for the gas flowing back through the oil passage to the oil chamber side to prevent the oil from flowing into the first oil dividing chamber through the first communication passage. Further, since the second communication passage is connected to the second oil division chamber, the gas staying in the second oil division chamber can be discharged out of the oil chamber via the second communication passage. Therefore, the oil on the cylinder head can easily flow into the first oil dividing chamber via the first communication path. Then, the oil that has flowed into the first oil dividing chamber flows into the second oil dividing chamber through the through hole, and is returned from the second oil dividing chamber into the oil pan through the oil passage. .

  Depending on the traveling mode of the vehicle, the vehicle may accelerate in the cylinder arrangement direction. In this case, on the cylinder head, the oil easily moves outward in the cylinder arrangement direction on the cylinder head due to the inertial force of the oil. Therefore, it is preferable to dispose the first communication path closer to the outside of the cylinder head in the cylinder arrangement direction than the second communication path.

  According to the above configuration, even when the vehicle accelerates in the cylinder arrangement direction, the oil on the cylinder head is maintained in a state where it can easily flow into the oil chamber via the first communication path, and the oil chamber It is possible to maintain a state in which the staying gas is easily discharged out of the oil chamber through the second communication path.

  Further, in the cylinder head, the temperature between the exhaust passages adjacent to each other in the cylinder arrangement direction is likely to be higher than the other portions due to the heat of the exhaust gas flowing through both exhaust passages. Therefore, the second communication passage is disposed between the exhaust passages adjacent to each other in the cylinder arrangement direction, and the first communication passage is disposed closer to the outside of the cylinder head in the cylinder arrangement direction than the exhaust passage. May be. According to this configuration, since the first communication passage is not disposed between the plurality of exhaust passages, it is possible to suppress the temperature rise of the oil flowing toward the oil chamber in the first communication passage. In addition, since the second communication path is not disposed closer to the outside of the cylinder head in the cylinder arrangement direction than the first communication path, an increase in size in the cylinder arrangement direction of the internal combustion engine can be suppressed.

  In addition, it is preferable that the passage cross-sectional area of the first communication path is larger than the cross-sectional area of the second communication path. According to this configuration, the oil on the cylinder head easily flows into the first communication path by increasing the cross-sectional area of the first communication path.

  When the concave portion is the first concave portion and the oil chamber is the first oil chamber, the cylinder block is provided with a second concave portion on one side in the cylinder arrangement direction with respect to the first concave portion. Sometimes. In this case, by closing the second recess with the cylinder head, it is possible to form a second oil chamber that is adjacent to the first oil chamber in the cylinder arrangement direction with a partition wall therebetween. A third communication path that opens to the upper surface of the cylinder head and communicates with the second oil chamber is provided in the cylinder head so that the oil path is connected to both the first oil chamber and the second oil chamber. In this case, the oil on the cylinder head can flow into the second oil chamber via the third communication passage, and the oil remaining in the second oil chamber can be returned to the oil pan via the oil passage. .

  In such a configuration, similarly to the first oil chamber, gas may flow from the oil pan side to the second oil chamber via the oil passage, and the gas may stay in the second oil chamber. . When the pressure in the second oil chamber increases, the gas staying in the second oil chamber may prevent the oil from flowing into the second oil chamber from above the cylinder head via the third communication path. There is.

  Therefore, in the on-vehicle internal combustion engine, it is preferable to provide a connection hole in the partition wall for communicating the first oil chamber and the second oil chamber. According to this configuration, the gas staying in the second oil chamber can be discharged to the first oil chamber side through the connection hole. As a result, the amount of gas staying in the second oil chamber can be reduced, and as a result, the gas staying in the second oil chamber causes the second oil chamber from above the cylinder head via the third communication path. It can suppress that the inflow of the oil to is prevented.

Note that the gas discharged from the second oil chamber to the first oil chamber through the connection hole is discharged to the outside through the second communication path.
In the above-described in-vehicle internal combustion engine, a portion between the extending wall on the upper surface of the cylinder head and the first opening position is formed so as to be positioned downward as the first opening position is approached in the cylinder arrangement direction. It may become. In this case, it is preferable to arrange the flow surface directly above the coolant passage provided inside the cylinder head.

  According to the above configuration, when the oil flowing into the cylinder head flows toward the first opening position along the flow surface, the oil is cooled by the cooling water flowing through the cooling water passage in the cylinder head. Therefore, the oil can be cooled in the process of returning the oil to the oil pan.

1 is a cross-sectional view schematically showing an embodiment of an internal combustion engine. The perspective view which shows typically a part of cylinder block of the internal combustion engine. The figure which shows typically the cross section of a cylinder block, and the cross section of a cylinder head in the internal combustion engine. The top view which shows typically a part of upper surface of the cylinder head of the internal combustion engine. FIG. 3 is an operation diagram showing how oil and gas flow in the internal combustion engine. The internal combustion engine of another embodiment WHEREIN: The figure which shows typically the cross section of a cylinder block, and the cross section of a cylinder head.

Hereinafter, an embodiment of an internal combustion engine will be described with reference to FIGS.
As shown in FIG. 1, in an internal combustion engine 10 mounted on a vehicle, a cylinder head 12 is attached to an upper portion of a cylinder block 11. A crankcase 13 is attached to the lower part of the cylinder block 11, and an oil pan 14 is attached to the lower part of the crankcase 13. The oil stored in the oil pan 14 is pumped up by an oil pump and supplied to a required portion of the oil in the internal combustion engine 10.

  As shown in FIGS. 1 and 2, a plurality (three in the present embodiment) of cylinders 15 (151, 152, 153) are provided in the cylinder block 11. The direction in which the cylinders 15 are arranged in the cylinder block 11 is referred to as “cylinder arrangement direction X”. Among the cylinders 15, the cylinder located on the most one side (right side in FIG. 2) in the cylinder arrangement direction X is referred to as a cylinder 151, and the cylinder located on the other side (left side in FIG. 2) in the cylinder arrangement direction X is cylinder 153. A cylinder located between the cylinder 151 and the cylinder 153 is referred to as a cylinder 152. A piston 16 that reciprocates in the vertical direction in FIG. 1 is provided in each of the cylinders 151 to 153. Each piston 16 is connected to a crankshaft 18 via a connecting rod 17. The crankshaft 18 is disposed in a space defined by the crankcase 13 and the oil pan 14.

  In the internal combustion engine 10, the combustion chamber 19 is defined by the peripheral walls of the cylinders 151 to 153, the piston 16, and the cylinder head 12. In each combustion chamber 19, an air-fuel mixture containing intake air introduced into the combustion chamber 19 through the intake passage 20 and fuel injected from the fuel injection valve is combusted. Exhaust gas generated in each combustion chamber 19 by such combustion of the air-fuel mixture is discharged to the exhaust passage 21.

  The intake passage 20 is opened and closed with respect to the combustion chamber 19 by an intake valve 22, and the exhaust passage 21 is opened and closed with respect to the combustion chamber 19 by an exhaust valve 23. The intake valve 22 operates in synchronization with the rotation of the cam shaft 24 for the intake valve 22. Further, the exhaust valve 23 operates in synchronization with the rotation of the cam shaft 25 for the exhaust valve 23.

  As shown in FIGS. 1 and 2, a block-side cooling water passage 31 that is a cooling water passage through which cooling water flows is provided in the cylinder block 11 so as to surround each of the cylinders 151 to 153. As shown in FIGS. 1 and 3, a head side cooling water passage 32, which is a cooling water passage through which cooling water flows, is provided in the cylinder head 12. In the present embodiment, a part of the cooling water flowing through the block side cooling water passage 31 flows into the head side cooling water passage 32.

  A direction orthogonal to both the extending direction of the central axis 15a of the cylinders 151 to 153 and the cylinder arrangement direction X is referred to as a prescribed direction Y. As shown in FIGS. 2 and 3, the first recess 41 and the second recesses arranged side by side in the cylinder arrangement direction X are located closer to the outside of the cylinder block 11 than the block-side cooling water passage 31 in the specified direction Y. The recess 42 is provided. The first recess 41 and the second recess 42 are adjacent to each other across the partition wall 43, and the second recess 42 is on one side (right side in FIG. 3) in the cylinder arrangement direction X with respect to the first recess 41. Has been placed. As shown in FIG. 2, the partition wall 43 is disposed between the central axis 15 a of the cylinder 151 and the central axis 15 a of the cylinder 152.

  As shown in FIG. 3, the recesses 41 and 42 are closed by the cylinder head 12. As a result, a first oil chamber 50 and a second oil chamber 60 that are adjacent to each other in the cylinder arrangement direction X are formed in the internal combustion engine 10. In the present embodiment, the oil chambers 50 and 60 are formed such that the volume of the second oil chamber 60 is smaller than the volume of the first oil chamber 50.

  Of the two ends of the first oil chamber 50 in the cylinder arrangement direction X, the end farther from the second oil chamber 60 (the left end in FIG. 3) is the cylinder of the cylinder block 11 than the central axis 15a of the cylinder 153. It is away from the center in the arrangement direction X. The depth of the first oil chamber 50, which is the length in the vertical direction of the first oil chamber 50, becomes deeper as it approaches the second oil chamber 60 in the cylinder arrangement direction X. The first oil chamber 50 is divided into a first oil dividing chamber 52 and a second oil dividing chamber 53 by a partition wall 51 provided in the cylinder block 11. The second oil dividing chamber 53 is disposed closer to the second oil chamber 60 than the first oil dividing chamber 52. Further, the first oil dividing chamber 52 and the second oil dividing chamber 53 communicate with each other through a through hole 51 a provided in the partition wall 51. In the present embodiment, the two through holes 51a are arranged in the vertical direction. Each through hole 51 a is formed so as to be positioned downward as it is away from the first oil dividing chamber 52 in the cylinder arrangement direction X. That is, the extending direction of each through hole 51 a is inclined with respect to the cylinder arrangement direction X.

  Of the two ends of the second oil chamber 60 in the cylinder arrangement direction X, the end farther from the first oil chamber 50 (the right end in FIG. 3) is the cylinder of the cylinder block 11 than the central axis 15a of the cylinder 151. It is away from the center in the arrangement direction X. The depth of the second oil chamber 60, which is the length in the vertical direction of the second oil chamber 60, becomes deeper as it approaches the first oil chamber 50 in the cylinder arrangement direction X.

  A portion below the partition wall 43 in the cylinder block 11 is a collecting portion 71 that connects the second oil dividing chamber 53 of the first oil chamber 50 and the second oil chamber 60. An oil flow path 72 (see FIG. 1) through which oil staying in the oil chambers 50 and 60 flows down to the oil pan 14 side is connected to the collecting portion 71. In other words, in the present embodiment, the oil collecting in the oil chambers 50 and 60 is connected to both the first oil chamber 50 and the second oil chamber 60 by the collecting portion 71 and the oil flow path 72. An example of an “oil passage 70” that returns to the oil pan 14 is configured. In the present embodiment, the oil passage 70 is connected to the second oil dividing chamber 53 of the first oil chamber 50, but is not connected to the first oil dividing chamber 52.

  Further, the partition wall 43 is provided with a connection hole 43 a that communicates the second oil dividing chamber 53 of the first oil chamber 50 with the second oil chamber 60. In the present embodiment, a plurality (two in FIG. 3) of connection holes 43a are arranged in the vertical direction. Each connection hole 43 a is disposed above the center of the partition wall 43 in the vertical direction. Furthermore, the extending direction of each connection hole 43a is inclined with respect to the cylinder arrangement direction X. Specifically, each connection hole 43 a is formed so as to be positioned downward as it approaches the second oil chamber 60.

  As shown in FIGS. 3 and 4, the cylinder head 12 includes a plurality of (three in FIG. 3) communication passages 55 that open to the upper surface 121 of the cylinder head 12 and are connected to the first oil chamber 50. 56 and 57 are provided. Each of the communication passages 55 to 57 extends substantially in the vertical direction. Further, the communication paths 55 to 57 are arranged side by side in the cylinder arrangement direction X. The first communication passage 55 of the communication passages 55 to 57 is connected to the first oil division chamber 52 of the first oil chamber 50, while the second oil division chamber 53. Not connected to. The remaining second communication passages 56 and 57 are connected to the second oil dividing chamber 53, but are not connected to the first oil dividing chamber 52. The passage cross-sectional area of the first communication passage 55 is wider than the passage cross-sectional area of the second communication passages 56 and 57.

  Note that the first communication path 55 is disposed closer to the outer side of the cylinder head 12 than the second communication paths 56 and 57 in the cylinder arrangement direction X (leftward in FIG. 3). In the example shown in FIG. 3, the number of the first communication paths 55 is one, and the number of the second communication paths 56 and 57 is two. The second communication passages 56 and 57 are arranged between the exhaust passages 21 adjacent to each other in the cylinder arrangement direction X. On the other hand, the first communication passage 55 is disposed closer to the outer side of the cylinder head 12 in the cylinder arrangement direction X than the exhaust passages 21 (leftward in FIG. 3).

  Further, the cylinder head 12 is provided with a third communication path 65 that opens to the upper surface 121 of the cylinder head 12 and is connected to the second oil chamber 60. The third communication path 65 is disposed on the opposite side of the first communication path 55 across the second communication paths 56 and 57 in the cylinder arrangement direction X. In other words, the third communication passage 65 is disposed closer to the outer side of the cylinder block 11 than the second communication passages 56 and 57 in the cylinder arrangement direction X (rightward in FIG. 3).

  In the present embodiment, there is only one third communication path 65. The passage cross-sectional area of the third communication passage 65 is larger than the passage cross-sectional area of the second communication passages 56 and 57 and is approximately the same as the passage cross-sectional area of the first communication passage. The third communication passage 65 is located on the opposite side of the partition wall 43 with the center of the second oil chamber 60 in the cylinder arrangement direction X, and in the cylinder arrangement direction X with respect to each exhaust passage 21. The cylinder head 12 is arranged on the outer side (right side in FIG. 3).

  Of the upper surface 121 of the cylinder head 12, a position where the first communication path 55 opens is a first opening position 55a, and a position where the second communication paths 56, 57 open is a second opening position 56a, 57a. The position where the third communication path 65 opens is defined as a third opening position 65a. As shown in FIG. 3, the upper surface 121 is formed so that the second opening positions 56a and 57a are located above the first opening position 55a and the third opening position 65a.

  As shown in FIGS. 3 and 4, the second opening position 56a close to the first opening position 55a among the plurality of second opening positions 56a and 57a on the upper surface 121, and the first opening position 55a. Is provided with a first extending wall 58 extending in a direction crossing the cylinder arrangement direction X. The first extension wall 58 corresponds to an example of an “extension wall” provided between the first opening position 55a and the second opening position 56a. The first extending wall 58 is disposed closer to the second opening position 56a than the middle between the second opening position 56a and the first opening position 55a in the cylinder arrangement direction X. More specifically, the first extending wall 58 is adjacent to the periphery of the second opening position 56a. As shown in FIG. 3, the portion of the upper surface 121 between the first opening position 55a and the first extension wall 58 is positioned downward as it approaches the first opening position 55a in the cylinder arrangement direction X. Thus, the first flow surface 59 is formed. The first flow lower surface 59 corresponds to an example of a “flow lower surface” located between the first opening position 55 a and the first extension wall 58 in the upper surface 121.

  Further, as shown in FIGS. 3 and 4, the second opening position 57a close to the third opening position 65a among the plurality of second opening positions 56a and 57a in the upper surface 121, and the third opening A second extending wall 68 extending in a direction intersecting with the cylinder arrangement direction X is provided between the position 65a. The second extending wall 68 is disposed closer to the second opening position 57a than the middle between the second opening position 57a and the third opening position 65a in the cylinder arrangement direction X. More specifically, the second extending wall 68 is adjacent to the periphery of the second opening position 57a. As shown in FIG. 3, the space between the third opening position 65 a and the second extending wall 68 on the upper surface 121 is positioned downward as it approaches the third opening position 65 a in the cylinder arrangement direction X. It becomes the 2nd flow lower surface 69 currently formed in this.

  As shown in FIG. 3, in the cylinder head 12, the head side cooling water passage 32 passes both directly below the first flow surface 59 and directly below the second flow surface 69. That is, the first flow surface 59 and the second flow surface 69 are arranged immediately above the head-side cooling water passage 32.

Next, with reference to FIG. 5, the operation and effect of the present embodiment will be described.
On the upper surface 121 of the cylinder head 12, the first opening position 55a and the third opening position 65a are located below the second opening positions 56a and 57a. In addition, a first extending wall 58 is disposed between the first opening position 55a and the second opening position 56a, and between the third opening position 65a and the second opening position 57a. A second extending wall 68 is disposed on the side. Therefore, on the upper surface 121, oil flows toward the first opening position 55a or the third opening position 65a. In other words, oil hardly flows toward the second opening positions 56 a and 57 a on the upper surface 121, and oil on the cylinder head 12 hardly flows into the second communication passages 56 and 57.

  Further, even if the amount of oil staying on the first opening position 55a side from the second opening position 56a on the cylinder head 12 is larger, the oil may flow into the second communication path 56. It is regulated by one extending wall 58. Similarly, even if the amount of oil that stays on the cylinder head 12 on the third opening position 65a side is larger than the second opening position 57a, the oil may flow into the second communication path 57. It is regulated by the second extending wall 68. Also in this respect, the oil on the cylinder head 12 is difficult to flow into the second communication passages 56 and 57.

  A part of the oil traveling toward the first opening position 55 a on the upper surface 121 flows on the first flow surface 59. In addition, a part of the oil traveling toward the third opening position 65 a on the upper surface 121 flows on the second flow surface 69. Since the flow lower surfaces 59 and 69 are disposed immediately above the head-side cooling water passage 32, the oil flowing on the flow lower surfaces 59 and 69 can be cooled by the cooling water flowing through the head-side cooling water passage 32. . Then, the oil that has reached the first opening position 55a flows into the first oil dividing chamber 52 of the first oil chamber 50 through the first communication passage 55 as shown by a solid line arrow in FIG. . The oil in the first oil dividing chamber 52 flows into the second oil dividing chamber 53 through the through hole 51 a and then returns to the oil pan 14 through the oil passage 70. Further, the oil that has reached the third opening position 65a on the upper surface 121 flows into the second oil chamber 60 through the third communication passage 65 as shown by a solid line arrow in FIG. Then, the oil in the second oil chamber 60 is returned into the oil pan 14 through the oil passage 70.

  By the way, when the engine rotational speed and the engine load factor increase, the amount of oil flowing into the cylinder head 12 increases, and therefore, from the cylinder head 12 toward the first oil chamber 50 via the first communication path 55. More oil will flow. Further, more oil flows from the cylinder head 12 toward the second oil chamber 60 via the third communication passage 65. Further, when the engine rotation speed or the engine load factor increases, the pressure in the crankcase 13 and the oil pan 14 increases. Therefore, blow-by gas in the crankcase 13 flows back through the oil passage 70 and flows into the first oil chamber 50 and the second oil chamber 60. As a result, the pressure in the first oil chamber 50 and the pressure in the second oil chamber 60 are increased.

  The first oil chamber 50 is divided into a first oil dividing chamber 52 and a second oil dividing chamber 53 by a partition wall 51. The oil passage 70 is connected to the second oil dividing chamber 53, but is not connected to the first oil dividing chamber 52. Therefore, the partition wall 51 restricts the gas such as blow-by gas that stays in the second oil dividing chamber 53 from flowing into the first oil dividing chamber 52. Therefore, it is possible to suppress the flow of oil from the cylinder head 12 through the first communication passage 55 to the first oil dividing chamber 52 through the gas staying in the first oil chamber 50 from being hindered. In FIG. 5, a region where gas is accumulated in the second oil dividing chamber 53 and the second oil chamber 60 is represented by a two-dot chain line.

  In the second oil dividing chamber 53, gas stays in the upper region. That is, gas stays in the vicinity of the connection portion between the second oil dividing chamber 53 and the second communication passages 56 and 57. As described above, oil does not flow into the second communication passages 56 and 57 from the cylinder head 12 so much. Therefore, the gas staying in the second oil dividing chamber 53 can be discharged out of the first oil chamber 50 through the second communication passages 56 and 57.

  Therefore, even if a large amount of oil flows into the first oil chamber 50 via the first communication passage 55 or a large amount of blow-by gas flows into the first oil chamber 50 via the oil passage 70. The gas staying in the second oil dividing chamber 53 is discharged to the outside of the first oil chamber 50 through the second communication passages 56 and 57, so that the increase in the pressure of the first oil chamber 50 is suppressed. be able to. As a result, the oil can be appropriately circulated through the first communication passage 55 and the first oil chamber 50. In addition, by reducing the amount of gas staying in the second oil dividing chamber 53 in this way, the content rate of the bubbles of oil returned from the second oil dividing chamber 53 into the oil pan 14 through the oil passage 70 Can be lowered.

  On the other hand, there is only one communication path connecting the second oil chamber 60 and the cylinder head 12, that is, the third communication path 65. That is, the resistance when the gas flows from the second oil chamber 60 to the cylinder head 12 via the third communication path 65 is reduced from the first oil chamber 50 via the communication paths 55 to 57. It is larger than the resistance when the gas is circulated above. Therefore, when a large amount of blow-by gas flows from the oil pan 14 side through the oil passage 70, the second gas from the cylinder head 12 through the third communication passage 65 is retained by the gas staying in the second oil chamber 60. There is a risk that the oil flow to the oil chamber 60 may be hindered.

  In this regard, in the present embodiment, the second oil chamber 60 communicates with the second oil dividing chamber 53 of the first oil chamber 50 through a connection hole 43 a provided in the partition wall 43. Therefore, even if the gas discharge performance from the second oil chamber 60 to the cylinder head 12 via the third communication passage 65 is low, the gas staying in the second oil chamber 60 is connected via the connection hole 43a. It can flow out to the second oil dividing chamber 53 side. Thus, the gas flowing into the second oil dividing chamber 53 is discharged onto the cylinder head 12 through the second communication passages 56 and 57. Thereby, it is possible to suppress the gas from staying in the second oil chamber 60. As a result, it is possible to suppress the flow of oil from the cylinder head 12 to the second oil chamber 60 through the third communication path 65 by the gas staying in the second oil chamber 60. Therefore, the oil that has flowed into the second oil chamber 60 via the third communication passage 65 can be appropriately returned into the oil pan 14 via the oil passage 70. Further, by reducing the amount of gas staying in the second oil chamber 60 in this way, the content rate of the bubbles of oil returned from the second oil chamber 60 through the oil passage 70 into the oil pan 14 is reduced. can do.

  In the second oil chamber 60, gas tends to stay in the upper region. In this regard, in the present embodiment, the connection hole 43a is disposed above the center of the partition wall 43 in the vertical direction. Therefore, the gas staying in the second oil chamber 60 can easily flow out to the second oil dividing chamber 53 through the connection hole 43a.

  Further, since the gas flowing into the second oil chamber 60 flows out into the second oil dividing chamber 53 through the connection hole 43a, the gas stays near the partition wall 43 in the second oil chamber 60. Cheap. In this regard, in the present embodiment, the connection portion of the second oil chamber 60 with the third communication path 65 is disposed on the opposite side of the partition wall 43 with the center of the second oil chamber 60 in the cylinder arrangement direction X. Has been. For this reason, even if the gas stays in the second oil chamber 60, it is difficult for the oil on the cylinder head 12 to flow through the third communication passage 65 to the second oil chamber 60. Further, due to the momentum of the oil flowing into the second oil chamber 60 through the third communication passage 65, the gas staying in the second oil chamber 60 is transferred to the second oil dividing chamber 53 side through the connection hole 43a. It becomes easy to extrude.

In the present embodiment, the following effects can be further obtained.
(1) The first oil chamber 50 and the second oil chamber 60 are respectively disposed near the block-side cooling water passage 31. Further, the connection portion of the first oil chamber 50 with the oil passage 70 is separated from the connection portion of the first oil chamber 50 with the first communication passage 55 in the cylinder arrangement direction X. Therefore, compared with the case where the connection part with the 1st communicating path 55 in the 1st oil chamber 50 is arrange | positioned near the connection part with the oil path 70 in the 1st oil chamber 50, it is compared with the 1st communicating path. The time for the oil flowing into the first oil chamber 50 through the passage 55 to stay in the first oil chamber 50 becomes longer. As a result, in the process in which oil flows toward the oil passage 70 in the first oil chamber 50, the oil can be cooled by the cooling water flowing through the block-side cooling water passage 31. Accordingly, relatively low temperature oil can be returned into the oil pan 14.

  (2) The passage cross-sectional area of the first communication passage 55 and the passage cross-sectional area of the third communication passage 65 are larger than the passage cross-sectional areas of the second communication passages 56 and 57, respectively. Therefore, compared with the case where the passage cross-sectional area of the first communication passage 55 and the passage cross-sectional area of the third communication passage 65 are approximately the same as the passage cross-sectional area of the second communication passages 56 and 57, the cylinder head 12. It becomes easy to return the upper oil into the oil pan 14 through the first communication path 55 and the third communication path 65.

  (3) Depending on the traveling mode of the vehicle on which the internal combustion engine 10 of the present embodiment is mounted, the vehicle may accelerate in the cylinder arrangement direction X. In this case, on the cylinder head 12, the oil tends to accumulate outside the center in the cylinder arrangement direction X due to the inertial force of the oil in the cylinder arrangement direction X. In this regard, in the present embodiment, the first communication path 55 and the third communication path 65 are disposed outside the second communication paths 56 and 57 in the cylinder arrangement direction X in the cylinder block 11. Yes. Therefore, even when acceleration in the cylinder arrangement direction X acts on the internal combustion engine 10, the oil staying on the cylinder head 12 passes through either the first communication path 55 or the third communication path 65. Thus, it is possible to maintain a state in which it is easy to flow into the oil chambers 50 and 60, and a state in which the gas staying in the second oil dividing chamber 53 is easily discharged to the outside of the oil chamber via the second communication passages 56 and 57 be able to.

  (4) Further, in the portion of the cylinder head 12 between the exhaust passages 21 adjacent to each other in the cylinder arrangement direction X, the temperature tends to increase due to the heat from the exhaust gas flowing through the exhaust passages 21. In this regard, in the present embodiment, since the first communication passage 55 is not disposed between the exhaust passages 21 adjacent to each other in the cylinder arrangement direction X, the first oil division is performed in the first communication passage 55. An increase in the temperature of the oil flowing toward the chamber 52 can be suppressed. In addition, since the second communication passages 56 and 57 are not disposed outside the cylinder head 12 in the cylinder arrangement direction X from the first communication passage 55, the increase in size of the internal combustion engine 10 in the cylinder arrangement direction X can be suppressed. it can.

This embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
In the above embodiment, the first flow surface 59 is formed so as to be gradually positioned downward as it approaches the first opening position 55a in the cylinder arrangement direction X. However, if the first flow surface 59 is formed so as to be positioned closer to the first opening position 55a in the cylinder arrangement direction X, it has a shape different from the shape described in the above embodiment. There may be. For example, the first flow surface 59 may be formed so as to be positioned stepwise downward as it approaches the first opening position 55a in the cylinder arrangement direction X.

  In the above embodiment, the second flow lower surface 69 is formed so as to be gradually positioned downward as it approaches the third opening position 65a in the cylinder arrangement direction X. However, as long as the second flow surface 69 is formed so as to be positioned closer to the third opening position 65a in the cylinder arrangement direction X, the shape is different from the shape described in the above embodiment. There may be. For example, the second flow surface 69 may be formed so as to be positioned stepwise downward as it approaches the third opening position 65a in the cylinder arrangement direction X.

The first extending wall 58 may be disposed at a midway position in the first flow surface 59 in the cylinder arrangement direction X.
The second extending wall 68 may be disposed in the middle position of the second flow surface 69 in the cylinder arrangement direction X.

  If the amount of oil flowing from the cylinder head 12 through the first communication passage 55 to the first oil chamber 50 can be sufficiently secured, the passage cross-sectional area of the first communication passage 55 is It is not necessary to make it wider than the cross-sectional area of the second communication passages 56 and 57. For example, the passage cross-sectional area of the first communication passage 55 may be equal to the passage cross-sectional area of the second communication passages 56 and 57, or may be narrower than the passage cross-sectional area of the second communication passages 56 and 57. Also good.

  If the amount of oil flowing from the cylinder head 12 through the third communication passage 65 to the second oil chamber 60 can be sufficiently secured, the cross-sectional area of the third communication passage 65 is It is not necessary to make it wider than the cross-sectional area of the second communication passages 56 and 57. For example, the passage cross-sectional area of the third communication passage 65 may be equal to the passage cross-sectional area of the second communication passages 56 and 57, or may be narrower than the passage cross-sectional area of the second communication passages 56 and 57. Also good.

  The oil in the first oil chamber 50 is closer to the connection portion with the second communication passages 56 and 57 in the first oil chamber 50 than the connection portion with the first communication passage 55 in the first oil chamber 50. If the connection portion with the passage 70 is arranged, the first communication passage 55 is arranged inside the cylinder block 11 inside the cylinder arrangement direction X with respect to the second communication passages 56 and 57. Also good.

  The oil passage 70 in the second oil chamber 60 is closer to the connection portion with the second communication passage 57 in the first oil chamber 50 than the connection portion with the third communication passage 65 in the second oil chamber 60. If the connection part is arrange | positioned, you may arrange | position the 3rd communicating path 65 in the cylinder arrangement | positioning direction X inside the cylinder block 11 rather than the 2nd communicating path 56,57. .

-The number of the 1st communicating paths 55 connected to the 1st oil division chamber 52 may be two or more arbitrary numbers (for example, two).
-The number of the 2nd communicating path connected to the 2nd oil division chamber 53 may be three or more arbitrary numbers (for example, four). Further, the number of the second communication passages may be one as long as the exhaust efficiency of the gas staying in the second oil dividing chamber 53 onto the cylinder head 12 can be sufficiently ensured.

  The partition wall 43 may be provided with three or more (for example, four) connection holes 43a. Further, the number of connection holes 43 a provided in the partition wall 43 may be one as long as a sufficient amount of gas outflow from the second oil chamber 60 to the second oil dividing chamber 53 can be secured.

  If the gas staying in the second oil chamber 60 can be appropriately discharged to the second oil dividing chamber 53 side, the connection hole 43a may be disposed at an intermediate position in the vertical direction of the partition wall 43. The connecting hole 43a may be disposed below the middle of the partition wall 43 in the vertical direction.

  If the rigidity of the cylinder block 11 can be sufficiently secured without providing the partition wall 51, the partition wall 51 may be omitted. In this case, the first oil chamber 50 is not divided into two oil dividing chambers 52 and 53.

  As shown in FIG. 6, the second oil chamber may be a second oil chamber 60 </ b> A shaped so that the depth at each position in the cylinder arrangement direction X is substantially the same. In this case, a connecting passage 75 that connects the second oil chamber 60 </ b> A and the oil passage 70 is provided in the cylinder block 11 along the partition wall 43.

  A plurality of communication passages that open on the cylinder head 12 and are connected to the second oil chamber 60 may be provided. In this case, when a communication path different from the third communication path among these communication paths is the fourth communication path, a connection portion of the second oil chamber 60 with the fourth communication path is Alternatively, the second oil chamber 60 may be disposed closer to the partition wall 43 in the cylinder arrangement direction X than the connection portion with the third communication passage 65 in the second oil chamber 60. In this case, the gas staying in the second oil chamber 60 can be discharged out of the second oil chamber 60 through the fourth communication path. Therefore, the connection hole 43 a may not be provided in the partition wall 43.

If the number of cylinders 15 provided in the cylinder block 11 is an odd number of three or more, the number of cylinders 15 may be an arbitrary number other than three (for example, five).
The number of cylinders 15 provided in the cylinder block 11 may be an even number (for example, four). In this case, the volume of the first oil chamber 50 may not be larger than the volume of the second oil chamber 60. For example, the volume of the first oil chamber 50 may be equal to the volume of the second oil chamber 60, or may be smaller than the volume of the second oil chamber 60.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder block, 12 ... Cylinder head, 121 ... Upper surface, 14 ... Oil pan, 15, 151-153 ... Cylinder, 21 ... Exhaust passage, 32 ... Head side cooling water passage, 41 ... First Recessed part 42 ... second recessed part 43 ... partition wall 43a ... connection hole 50 ... first oil chamber 51 ... partition wall 51a ... through hole 52 ... first oil dividing chamber 53 ... second Oil dividing chamber, 55 ... first communication passage, 55a ... first opening position, 56,57 ... second communication passage, 56a, 57a ... second opening position, 58 ... first extension wall, 59 ... 1st flow surface, 60, 60A ... 2nd oil chamber, 65 ... 3rd communicating path, 70 ... Oil path.

Claims (8)

The oil chamber is formed by closing the recess provided in the cylinder block with the cylinder head,
The cylinder head is provided with a plurality of communication passages that are open on an upper surface of the cylinder head and connected to the oil chamber, and are arranged in a cylinder arrangement direction that is a direction in which a plurality of cylinders are arranged in the cylinder block. The communication paths are arranged in
The cylinder block is provided with an oil passage for returning the oil staying in the oil chamber into the oil pan.
The first opening position on the upper surface of the cylinder head, which is the position where the first communication path of the communication paths opens, is the second communication position of the communication paths on the upper surface of the cylinder head. Positioned below the second opening position, which is the position where the passage opens, and intersects the cylinder arrangement direction between the first opening position and the second opening position on the upper surface of the cylinder head. An in-vehicle internal combustion engine provided with an extending wall extending in the direction of the vehicle. The connection portion with the oil passage in the oil chamber is located closer to the connection portion with the second communication passage in the oil chamber than the connection portion with the first communication passage in the oil chamber. The in-vehicle internal combustion engine according to claim 1. The cylinder block is provided with a partition wall that partitions the oil chamber into a first oil partition chamber and a second oil partition chamber adjacent to the first oil partition chamber in the cylinder arrangement direction. And
While the first communication passage is connected to the first oil dividing chamber, the second communication passage and the oil passage are not connected,
While the first communication passage is not connected to the second oil dividing chamber, the second communication passage and the oil passage are connected,
The in-vehicle internal combustion engine according to claim 2, wherein the partition wall is provided with a through hole that allows the first oil dividing chamber and the second oil dividing chamber to communicate with each other. The in-vehicle internal combustion according to any one of claims 1 to 3, wherein the first communication path is disposed closer to the outside of the cylinder head in the cylinder arrangement direction than the second communication path. organ. The second communication passage is disposed between exhaust passages adjacent to each other in the cylinder arrangement direction,
The in-vehicle internal combustion engine according to any one of claims 1 to 4, wherein the first communication passage is disposed closer to the outside of the cylinder head in the cylinder arrangement direction than the exhaust passage. The in-vehicle internal combustion engine according to any one of claims 1 to 5, wherein a passage cross-sectional area of the first communication passage is larger than a passage cross-sectional area of the second communication passage. When the recess is the first recess and the oil chamber is the first oil chamber, the cylinder block is provided with a second recess on one side in the cylinder arrangement direction from the first recess. And
By closing the second recess with the cylinder head, a second oil chamber is formed adjacent to the first oil chamber in the cylinder arrangement direction with a partition wall therebetween.
The cylinder head is provided with a third communication path that opens to the upper surface of the cylinder head and communicates with the second oil chamber.
The oil passage is connected to both the first oil chamber and the second oil chamber,
The in-vehicle internal combustion engine according to any one of claims 1 to 6, wherein the partition wall is provided with a connection hole that communicates the first oil chamber and the second oil chamber. A portion of the upper surface of the cylinder head between the extending wall and the first opening position is formed such that the lower surface is located closer to the first opening position in the cylinder arrangement direction. And
The in-vehicle internal combustion engine according to any one of claims 1 to 7, wherein the flow surface is disposed immediately above a cooling water passage provided inside the cylinder head.